Impeller sensor for fluid pump

ABSTRACT

This disclosure describes electrically powered fluid (liquid) pumps having an electric motor or actuator attached to a power source with a power sensor configured to measure the power draw of the motor while the pump is operating.

This application claims priority benefit of U.S. Ser. No. 15/476,501,filed Mar. 31, 2017, incorporated herein by reference.

U.S. application Ser. No. 15/476,501 claims priority benefit of U.S.Ser. No. 62/318,013, filed Apr. 4, 2016, incorporated herein byreference.

BACKGROUND OF THE DISCLOSURE Field of the Disclosure

This disclosure relates to the field of electrically powered fluid(liquid) pumps having an electric motor or actuator which is attached toa power source with a power sensor configured to measure the power drawof the motor while the pump is operating.

BRIEF SUMMARY OF THE DISCLOSURE

Disclosed herein is an impeller sensor for a (fluid impeller) pump. Thepump optionally having an electric motor and an impeller for pumping offluid. In one example, the sensor has positive and negative electricpower input leads coupled to an electric power source such as householdAC power, a motor-driven generator, a battery, solar cell, or otherelectric power source. The term “lead” is used herein to define an oftenflexible and insulated single conductor, as a wire, used in connectionsbetween pieces of electric apparatus.

The impeller sensor has a power sensor electrically coupled to the powerinput leads. The power sensor is configured to sense/detect/analyze thepower draw of the impeller pump while the impeller pump is operating,and operate a switching circuit to selectively control power to theelectric motor of the impeller pump.

Positive and negative power output leads are electrically coupled to,and provide motive power to the impeller pump.

A timer may also be provided. The timer configured to provide motivepower to the impeller pump through the power output leads of theimpeller sensor at a predetermined time interval.

Circuitry is provided, configured to continue motive power to theimpeller pump through the power output leads when the power draw of theimpeller pump sensed by the power sensor is above a first threshold; andthe circuitry is configured to discontinue motive power to the impellerpump through the power output leads when the power draw of the impellerpump sensed by the power sensor falls below a second threshold.

The impeller sensor as recited above may be arranged wherein the timeris configured with: a first time interval; and a second time intervalsignificantly longer than the first time interval. The circuitry may beconfigured to actuate the timer upon discontinuation of motive power tothe impeller pump.

The circuitry of the impeller sensor may be configured to actuate theimpeller pump upon passing of a first time interval if the power sensordid detect power draw of the impeller pump above the first thresholdduring the previous actuation of the impeller pump.

The impeller sensor as recited above may be arranged wherein the powersensor is mounted at a location remote from the impeller pump.

The impeller sensor as recited above may be arranged wherein the timeris mounted at a location remote from the impeller pump.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is an exploded highly schematic view of one example of animpeller sensor fora liquid pump.

FIG. 2 is a process flow diagram of one example of the disclosedimpeller sensor for a liquid pump system.

DETAILED DESCRIPTION OF THE DISCLOSURE

Disclosed herein is an impeller sensor used for controlling a liquidimpeller pump having an electric motor and an impeller for pumping ofliquid. The sensor indirectly measures the presence of fluid (liquid,often water or fuel) in a vessel to be pumped from, such as a boat, drydock, etc. The sensor is used to determine the power draw of the pump,and then cease, or continue pumping of the liquid based on the powerconsumption of the pump, as compared to a baseline power consumption.For example, where the baseline is established via a dry pump, powerconsumption above a threshold over the baseline will result in continuedactuation of the pump. In another example, where the baseline isestablished via a wet pump, power consumption below a threshold belowthe baseline will result in terminating actuation of the pump.

Looking to FIG. 1 is shown one example of the disclosed impeller sensor20 electrically coupled to an impeller pump 22, although the sensor 20may be used with other liquid pumps. In FIG. 1 is shown a highlyschematic impeller pump 22, similar in function to prior known impellerpumps such as the impeller pumps disclosed in U.S. Pat. No. 7,866,942incorporated herein by reference. An impeller is generally a rotatingcomponent of a pump, which transfers energy from a motor driving theimpeller of the pump to the fluid (liquid or gas) being pumped. This isaccomplished in some pumps by accelerating the fluid outwards from thecenter of rotation. The fluid velocity achieved by the impellertransfers into pressure when the outward movement of the fluid isconfined by the pump housing. A detent on the inner surface of the pumphousing may also compress the space defined by the surfaces and thevanes of the impeller, thus forcing fluid out of the outlet 34.Impellers are usually fitted into short cylinders within the housing,the cylinders having an open inlet to accept incoming fluid, vanes topush the fluid into an outlet, and a splined, keyed, or threaded bore toaccept a drive-shaft connected to the motor. Impeller pump 22 shown inFIG. 1 comprises a drive motor 24 having a drive shaft 26 extendingtherefrom. The drive shaft 26 is coupled to an impeller 28 fitted withina pump housing 30 having an inlet 32 and an outlet 34. A gasket 36 orseal may be provided between the drive motor 24 and the pump housing 30to more effectively fluid seal the gap there between. Similarly, agasket 36 may be provided between the pump housing 30 and an end plate38. In one form, the end plate 38, gasket 36, pump housing 30, and drivemotor 24 are fixed together by way of fasteners as is well-known in theart.

As the impeller 28 rotates within an inner surface 40 of the pumphousing 30, fluid is pumped from the inlet 32 and exits the outlet 34.As can be appreciated by one of ordinary skill in the art, the powerconsumption of the drive motor 24 can be expressed where the powerequals the current flow times the voltage (P=IV). This power consumptionis significantly different between an impeller 28 which is pumping airor other gasses and an impeller 28 which is pumping a fluid/liquid suchas water or fuel. Thus, by determining a threshold power consumptiondifference between pumping of air (a dry impeller) and pumping of liquid(a wet impeller) the presence of pumping liquid in the pump housing 30can be determined during operation (rotation) of the impeller 28.

Disclosed herein in one example is an impeller sensor 20 for a liquidimpeller pump 22 to replace previously known float and pumpcombinations. The liquid impeller pump 22 having an electric (drive)motor 24 and an impeller 28 with vanes 42 extending radially from a hub44. The impeller 28 is attached to the drive shaft 26 of the drive motor24. The liquid impeller pump 22 is generally used for pumping of fluid,most commonly liquid. In one example, the impeller sensor has positive46 and negative 48 electric power input leads coupled to an electricpower source 50 such as household AC power, a motor-driven generator, amotor-driven alternator, a battery, power cell, solar cell, or otherelectric power source 50.

The impeller sensor 20 in one example has a power sensor 52 electricallycoupled to the power input leads 46/48. The power sensor 52 isconfigured to sense/detect/analyze the power draw of the impeller pumpdrive motor 24 while the impeller pump drive motor 24 is operating, andsubsequently send a control signal to a switching circuit 54 toselectively control power from the electric power source 50 to theelectric (drive) motor 24 of the pump 22.

The impeller sensor 20 in one example is coupled to positive poweroutput lead 56 and negative power output lead 58 which in turn areelectrically coupled to, and provide motive power to the drive motor 24.

A timer 60 may also be provided electrically coupled to the power sensor52 and switching circuit 54. The timer 60 is configured to periodicallyprovide motive power to the drive motor 24 of the impeller pump 22. Inone example electric motive power is provided to the drive motor 24through the power output leads 56/58 of the impeller sensor 20 at apredetermined time interval.

To facilitate operation, circuitry within the impeller sensor 20 isprovided, configured in one example to continue motive power to theimpeller pump through the power output leads 56/58 when the amperage orvoltage draw of the impeller pump drive motor 24 sensed by the powersensor 52 is above a first threshold. In this example, the circuitry isconfigured to discontinue motive power to the impeller pump through thepower output leads when the power draw of the impeller pump sensed bythe power sensor falls substantially below the first threshold. Thecircuitry may be configured to discontinue motive power to the impellerpump 22 through the power output leads 56/58 when the power draw of theimpeller pump drive motor 243 sensed by the power sensor 52 falls belowa second threshold, below the first threshold.

The impeller sensor 20 as recited above may be arranged wherein thetimer 60 is configured with: a first time interval; and a second timeinterval significantly longer than the first time interval. For example,after a first interval (i.e. 5 minutes) the timer 60 provides motivepower to the drive motor 24 for a short time duration, such as less than5 seconds. In one example this is accomplished by actuating theswitching circuit 54 for the short time duration. If during activation,the power sensor 52 detects a power draw above the first threshold powerthen the power sensor 52 will control the switching circuit 54 andmaintain actuation of the drive motor 24 while the power draw is abovethe first threshold. The circuitry may be configured to actuate a waitsequence defined by the first time interval upon discontinuation ofmotive power to the impeller pump following a pumping cycle thatdetermined the presence of liquid.

If actuation of the drive motor 24 for a short duration does not resultin a power draw above the first threshold power, then the wait sequenceof the timer is reset so as to send motive power to the drive motor 24after a wait sequence defined by a period of the second time interval.

In other terms, the impeller sensor will periodically energize the drivemotor 24. If the power sensor 52 detects a power draw above the firstthreshold, then it will continue energizing the drive motor 24 until thepower draw drops below a first threshold. If a second threshold is set(lower than the first threshold) then the impeller sensor 20 maycontinue energizing the drive motor 24 until the power draw falls belowthe first threshold, until the power draw drops below the secondthreshold.

Following actuation of the drive motor 24 and detection of power drawabove the first threshold, it is concluded that liquid (often water) ispresent in the region (often the bilge, sump, or dry dock) from whichliquid is pumped. Such liquid possibly indicating a leak, rain, orsimilar liquid entry. This subsequent actuation will be desired in arelatively short (first) interval. As it is mechanically andelectrically detrimental to run such pumps continually, a period of downtime is desired. In one range this first time interval is between oneand twenty minutes.

Following actuation of the drive motor 24 without detection of powerdraw above the first threshold, it is concluded that liquid (oftenwater) is not present in the region (often the bilge, sump, or dry dock)from which liquid is pumped. This subsequent actuation will be desiredin a relatively long (second) interval. In one range this second timeinterval may be between twenty minutes and ten hours.

Again, the circuitry of the impeller sensor 20 may include a timer 60configured to actuate the impeller pump upon passing of the first timeinterval, if the power sensor does detect power draw of the impellerpump above the first threshold during the previous actuation of theimpeller pump.

Similarly, circuitry of the impeller sensor may include a timer 60configured to actuate the impeller pump upon passing of second timeinterval (shorter than the first time interval) if the power sensor diddetect power draw of the impeller pump above the first threshold duringthe previous actuation of the impeller pump.

The impeller sensor as recited above may be arranged wherein the powersensor 52 is mounted at a location remote from the impeller pump 22, asthe impeller pump 22 is often positioned within a cavity such as avessel bilge, sump, or dry dock.

One such environment in which this impeller sensor 20 is particularlysuited is disclosed in U.S. Pat. No. 8,739,724 where the water pump (82)may comprise the drive motor 24 with impeller pump 22. In this exampleand others, the cavity (62) into which the impeller pump 22 is placed isoften at least partially filled with water, and nearly never fully dry.Previously, a float switch is often placed in the cavity with the waterpump (82). As the liquid (water) level rises in the cavity (62) thefloat switch activates the pump and the water level drops. The sensor ofthese previous configurations is electrically, and often mechanicallycoupled to the pump (82) and thus is susceptible to deterioration due towet conditions and electrolysis.

Such wet and damp conditions are very detrimental to the electricalcomponents of the impeller sensor 20 including the power sensor 52,switching circuit 54, and timer 60. Thus, it is often beneficial toprovide the power sensor 52, switching circuit 54, and/or timer 60exterior of the cavity from which liquid is to be pumped to deducedeterioration effects.

In one form, each of the power sensor 52, switching circuit 54, and/ortimer 60 may be provided in a watertight housing 64. In one example,each may be provided on the same circuit board and encapsulated in awatertight housing with leads 46/48 and 56/58 being the only extensionsthrough the housing.

The impeller sensor 20 as recited above may be arranged wherein thetimer 60, power sensor 52, and switching circuit 54 are each mounted atlocations remote from the impeller pump 22.

While the present invention is illustrated by description of severalembodiments and while the illustrative embodiments are described indetail, it is not the intention of the applicants to restrict or in anyway limit the scope of the appended claims to such detail, additionaladvantages and modifications within the scope of the appended claimswill readily appear to those sufficed in the art. The invention in itsbroader aspects is therefore not limited to the specific details,representative apparatus and methods, and illustrative examples shownand described. Accordingly, departures may be made from such detailswithout departing from the spirit or scope of applicant's generalconcept.

The invention claimed is:
 1. An impeller sensor for a liquid pumpcomprising: positive and negative electric power input leads coupled toan electric power source; positive and negative power output leadselectrically coupled to and configured to provide a motive power to theliquid pump; a power sensor coupled to the power input leads, the powersensor configured to sense the power draw of the liquid pump while theliquid pump is operating during a pumping cycle; a timer configured toprovide the motive power to the liquid pump through the power outputleads; circuitry configured to continue the motive power to the liquidpump through the power output leads when the power draw of the liquidpump sensed by the power sensor is above a first threshold, thuscontinuing the pumping cycle; the circuitry configured to discontinuethe motive power to the liquid pump through the power output leads whena power draw of the liquid pump sensed by the power sensor is below asecond threshold, thus ending the pumping cycle; the circuitryconfigured to actuate the timer upon discontinuation of the motive powerto the liquid pump; the timer configured to discontinue the motive powerto the liquid pump through the power output leads for a first wait timeinterval or a second wait time interval; the circuitry configured toactuate the liquid pump upon passing of the first wait time intervalfollowing the power sensor detecting the power draw of the liquid pumpabove the first threshold during a previous actuation of the liquidpump; and the circuitry configured to actuate the liquid pump uponpassing of the second wait time interval following the power sensordetecting power draw of the liquid pump above the first threshold duringthe previous actuation of the liquid pump.
 2. The impeller sensor asrecited in claim 1, wherein the liquid pump is an impeller pump havingan electric motor and an impeller.
 3. The impeller sensor as recited inclaim 1, wherein the power sensor is mounted at a location remote fromthe liquid pump.
 4. The impeller sensor as recited in claim 3, whereinthe timer is mounted at a location remote from the liquid pump.
 5. Theimpeller sensor as recited in claim 1, wherein the timer is mounted at alocation remote from the liquid pump.
 6. The impeller sensor as recitedin claim 1, wherein the liquid pump is positioned in a bilge of avessel.
 7. The impeller sensor as recited in claim 6, wherein the vesselis a dry dock.
 8. The impeller sensor as recited in claim 7, wherein thedry dock is a floating dry dock.
 9. The impeller sensor as recited inclaim 8, wherein the floating dry dock is inflatable.